Electrochemically prepared copper/indium oxides photocathode for efficient photoelectrochemical hydrogen production

摘要

A novel photocathodic composite has been studied towards photoelectrochemical (PEC) hydrogen production from water. Copper oxide/indium oxide (CuO/In2O3) thin film photocathodes have been prepared by electrochemical method under various potentials, followed by the thermal treatment. Photocathodes were characterized using X-ray powder diffraction (XRD) and scanning electron microscopy with elemental mapping. Under irradiation in alkaline electrolyte Cu/In material showed an impressive cathodic photocurrent, up to 4 mA cm(-2), which can be associated with efficient electron-hole pairs separation and low rate of unfavorable recombination. Photogenerated electrons induced a water reduction to hydrogen, as confirmed by gas chromatography. Photoactivity of Cu/In was observed in a broad wavelength range, partially corresponding to the UV-Vis spectrum obtained from diffuse reflectance spectroscopy. Advanced techniques such as synchrotron-radiation X-ray absorption spectroscopy enabled the investigation of materials stability. Under irradiation of Cu/In composite, Cu-II is partially reduced to Cu-I, leading to a formation of self-stabilized composite.